Printing ink



faten ted May 2,

UNITED STATES PATENT OFF E bauer, Jr., Union City, N. J., assignors'gtoInterchemical Qorporation, New York, N. Y., a corporation of Ohio 1N0Drawing. Application May 8, 1947, S erial No. 4746;858

4 'Claims.

This invention relates to printing ,inks, and

aims to provide typographic and lithographic ,flprinting inkofithesolven't resintype character- ,ized particularly by extremelyrapid drying undcler heat.

Typographic and lithographic printing inks iwere, untila short time ago,made almost ex- :clusively from drying oils. ,Recently, however, dryingoil inks have been largely supplanteiparticularly in the field ofmagazine printing, by

links of the typedisclosed in the Gessler ,U. S.

,LPatent No. 2,087,190; the vehicles ofth'ese inks icomprise essentiallysolutions of binder in olvent which is relatively non-volatile atordinary :room temperature (ca. 20 0.), but which volatilizes veryrapidly from films (like ethyl alcohol lat 20 ,C'.) when heatedtotemperatures of the order of 150 C. These inks are ordinarilyap- ,;pliedto paper and the likefrom conventional typographic printing presses,and, the printsare ithen passed through ovens heated to 1000*2000" atsuch a speed that the paper doesnot ex- ,sceed its scorchingpoint.Thesolventin; the ink,

,which is non-volatile a room \temperatura so that the ink remainsstable on thepress vapob iz s almost immediately from the thin films at;.the elevated temperatures, thus drying the ink.

:Flhe problem of lithographic printing with 22,285,430, issued June9,1942; the inksitherein :disclosed have vehicles which comprise resinsdissolved in specially treated 'petroleum hydrocaribons which have thecontent of aromatic and unsaturated compounds reduced to a dimethylsulfate value of 4 or 1ess, and preferably to a di- :methyl sulfatevalue of 1 or less.

in the formulation of this type ofink for either typographic orlithographic printing, the choice of resin is extremely important, sinceresins vary considerably in their solvent retentionflthus, us- :ing thesame solvent, inks made from two different resins may dry at somewhatdifierent rates. Furthermore, resins vary in solubility so that it mayrequire more or less solvent to obtain a given body, and more or lesssolvent may have to be evaporated to get ayfilmof thenecessaryrdry'ness. In general, it has been the experience of th'e artthat in order to obtainthe-desirable drying char- 5 acteristics,relatively ea'pensive resins are necessary.

issued October-i 15, 1946,1inks of-this type arepdescribed whichemployresins derived from-:Utah coals, dissolved inipetroleum hydrocarbonswhich are substantially; non-drying at '20 C.,: and. which evaporaterapidlyat 150 0., theseinhs are irelativelyinexpensive, yetdry-as wellas the best of the synthetic resinsheretofore available. In further workwith these resins in printing ink, we have discovered how to produceinks V which dry very much moreirapidly underlie-at than the very bestpetroleum lhydrocarboneresin inks heretofore available, dryingwith asr'nuchgas 40% less heat than knowm'esiris.

Our new fastdrying inks comprise dispersions of pigment in solutions ofcertain Utah coal resins in petroleum hydrocarbons which are slo wdrying tosubstantially non-drying at 20irC.;= but which evaporaterapidly at ,150 C. The resins used in turn-are the fractions-derivedfromY-fltah coal resins which are precipitated on dilution of ;a 25-45%isohexanesolution of the solub1ecoal resins to 10% concentration.

hod o e arin the ie n is ,described and claimed in j our copendl ngapplication i No '7&6;8 7.fi1 ;Me 947- In eneral, the method involvesisolating the in soluble resin fromthe crude resin obtaine, Joy flfrothflotation ofUtah coal, Illn "the form, of a concentrated solution, e, g.25-45% inisohekane. On dilutionto 10%, a fraction precipitates, which isa resinof thelclass used inthe inks of this 40 invention. The resin isof high melting point and is insoluble in] isohexane in the absence ofthe lower melting resins Typical exampleslpf the inks made in,accordancawith thejinvention are the, following: :Ewamplel Typically, a35% solution of hexane soluble coal resin, which is dissolved inZ-methyl pentane, will yield, on dilution to 10%, 18% of precipitated i0resin with a melting point of 240-260 C.

Example II.Va1'msh 38.75% precipitated coal resin of Example I 61.25%petroleum slvent-Boiling range (5- 95%) 245259 C.Kauri Butanol value 26The resin is melted and reduced with the solvent. The varnish has aviscosity of about 12 poises.

Example III .-Blaclc ink Parts by weight Varnish of Example II 67.4Paraifin wax 2.5 Talc 2.5 Lamp black 1.8 Carbon black 12.4 Iron blue 5.3

Toner-40% alkali blue, 60% varnish of Example II 4.5 Solvent of ExampleII 3.6

The material is ground on a three roll mill in conventional fashion.

It was tested on a proving press, and found to be stable for about 35minutes; prints could be dried by passing through a laboratory heater ata speed of about 750 feet per minute.

' Example IV.-Black ink Example III was reproduced, except 5 parts ofthe varnish was replaced by bodied linseed oil (litho oil) and 0.6 partby lecithin.

This ink was compared with an identical ink in which the varnish wasreplaced by a synthetic resin varnish in the same solvent, using one ofthe best of the commercial synthetic resins available for this purpose.Under the identical conditions used with Example III, Example IV wasstable 50 minutes, the known synthetic resins ink 60 minutes; Example IVink dried at 750 feet per minute, and the regular ink at 450 feet perminut'e. The finish of the regular ink was not as good as that ofExamples III and IV.

Example V.Yellow ink 140% by weight varnish of Example II 60% by weightPrimrose chrome yellow gave a printable ink which was rather dirty owingto the dark color of the varnish.

dicated range can be used, as well as other pigments, surface-activeagents, waxes and the like. Furthermore, additions of oils and resinscan also be made without losing the benefits of our invention providedthey are not of major proportion in relation to the special coal resinfraction.

We claim:

1. A printing ink comprising pigment dispersed in a vehicle, whichcomprises a solution of a resin in a petroleum hydrocarbon which is slowdrying to substantially non-drying at 20 C., but which volatilizes veryrapidly at C., the resin comprising the fraction of Utah coal resinwhich is precipitated on dilution of a. 25-45% solution of the coalresin in isohexane to 10% concentration with isohexane.

2. A printing ink comprising pigment dispersed in a vehicle, whichcomprises a solution of a resin in a petroleum hydrocarbon which is slowdrying to substantially non-drying at 20 C., but which volatilizes veryrapidly at 150 (3., the said resin comprising a resin derived fromresin-bearing coals of the Utah type, and being obtained from said coalsby a process comprising separating the crude resin from the bulk of thecoal to produce a resin concentrate of resin admixed with coal,separating the soluble resin content of the concentrate in the form of aclear isohexane solution containing 25 to 45 per cent of resin, dilutingthe clear resin solution to about 10 per cent concentration withisohexane, and recoverin the precipitated resin. 7

3. A printing ink comprising pigment dispersed in a vehicle, whichcomprises a solution of a resin in a petroleum hydrocarbon which is slowdrying to substantially non-drying at 20 C., but which volatilizes veryrapidly at 150 C., the said resin comprising a resin derived fromresin-bearing coals of the Utah type and being obtained from said coalsby a process comprising separating the crude resin from the bulk of thecoal to produce a resin concentrate of resin admixed with coal,dissolving the soluble resin content of the concentrate in a hydrocarbonsolvent to form a 25 to 45 per cent solution, separating the insolublematter, evaporating the solvent to obtain a dry resin, redissolving thedry resin in isohexane to obtain a 25 to 45 per cent solution, dilutingthe clear resin solution to about 10 per cent concentration withisohexane, and recovering the precipitated resin. v

4. A printing ink comprising pigment dispersed in a vehicle, whichcomprises a solution of a resin in a petroleum hydrocarbon which is slowdrying to substantially non-drying at 20 C., but which volatilizes veryrapidly at 150 C., the said resin comprising a resin derived fromresin-bearing coals such as are found in Utah, having a melting point ofthe order of 240-260 C., which is insoluble in isohexane, and which isfurther characterized by being soluble, together with the lower meltingresins of the coal, in isohexane at 25 .to 45 per cent total resinconcentration at room temperature, but being precipitated on dilution ofsuch solution to 10 per cent concentration with isohexane.

ERNEST D. LEE. RUPERT J. SCHEFBAUER, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

1. A PRINTING INK COMPRISING PIGMENT DISPERSED IN A VEHICLE, WHICHCOMPRISES A SOLUTION OF A RESIN IN A PETROLEUM HYDROCARBON WHICH IS SLOWDRYING TO SUBSTANTIALLY NON-DRYING AT 20* C., BUT WHICH VOLATILIZES VERYRAPIDLY AT 150*C., THE RESIN COMPRISING THE FRACTION OF UTAH COAL RESINWHICH IS PRECIPITATED ON DILUTION OF A 25-45% SOLUTION OF THE COAL RESININ ISOHEXANE TO 10% CONCENTRATION WITH ISOHEXANE.